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Old 05-10-2012, 12:16 PM
ontarget ontarget is offline
Join Date: Jun 2001
Posts: 1,405
Bolt-over-base malfunction

I've been testing a government model lightweight (Springfield Armory) and have experienced a few bolt-over-base (or breach/slide over base if you prefer to call it that) malfunctions.

This malfunction has only occurred with the last cartridge to feed from the magazine. I'm using fairly new Chip McCormick Power Mags and the malfunction has occured with three different mags.

I would normally attribute this to a weak mag spring not lifting the cartridges fast enough, but these mags all run flawlessly in other pistols.

I'm using the factory recoil spring, which feels like a 16lb spring by comparison to other pistols. No shock-buffer of any type.

Any ideas or suggestions are welcome.

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Old 05-10-2012, 12:53 PM
Rideandshoot Rideandshoot is offline
Join Date: Mar 2012
Posts: 141
My 40S&W Ultra Carry has the exact same issue. Only on the last round in the magazine. As of this time I seem to have resolved it by loading some cartridges .030 longer than factory. I'm using the same bullet as my carry ammo... 155g Hornady TAP. I'd be interested in other possible fixes.

One thing I intend to try is different recoil springs. It currently has a 21lb recoil spring so I will try a 18lb next. Seems like it has to be a timing issue.
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Old 05-10-2012, 03:44 PM
Flamz Flamz is offline
Join Date: Aug 2008
Location: NE Pa
Posts: 427
I've had the same problem. Experimented with recoil springs, magazine springs, flat firing pin stops, ammo, and magazines. The pistol was finally fixed by installing an EGW "raised" mag release. Holds the mag .020 higher in the well. Make sure the top round does not hit the ejector. Pistol has eaten everything for over 3.5K rounds. I'm not saying it will fix it but, it did for me.

Last edited by Flamz; 05-10-2012 at 03:49 PM.
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Old 05-10-2012, 06:50 PM
herd48 herd48 is offline
Senior Member
Join Date: Sep 2005
Location: West By God Virginia
Posts: 4,669
Check extractor tension. I am a springfield guy. Own a number. But I'm not fond of the stock extractors. I usually replace them almost immediately. Years ago I would tune them, but they didn't seem to hold a tuning well.
I'm the NRA
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Old 05-10-2012, 10:59 PM
ontarget ontarget is offline
Join Date: Jun 2001
Posts: 1,405
Extractor geometry and tension are good. With this malfunction the rim never gets near the extractor.
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Old 05-11-2012, 10:44 AM
tchostler tchostler is offline
Senior Member
Join Date: Feb 2009
Location: Illinois
Posts: 1,953
First thing to do is drop your recoil spring by a couple pounds and retest. If it still malfunctions, replace the mag spring with an Xtra power Wolff spring and retest. I did both on my commander that was doing the same thing. Now it functions flawlessly.
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